PHILADELPHIA -- Eagles coach Chip Kelly hasn't had a single player go down with a heat-related illness -- or any injury for that matter -- through the first two days of mandatory minicamp as temperatures reached well into the 90s at the Novacare Complex.

"We monitor every single guy on our team," Kelly said. "We monitor every player in terms of where they are so we know where those guys are. But those guys have done a great job from a recovery standpoint so they are ready to go today."

"Coach Chip Kelly puts a big importance on hydration," Pratt said. "We take a test every morning. You wake up, pee in a bottle and see what your hydration levels are. Coach Kelly harps on that every day: hydration, hydration, hydration.

"It shows on the field. You don't see anybody getting IVs. It's crazy when you think about all the running we do. People are out there flying around."

Such collections have become more common around the NFL. (The urine samples are only used to evaluate hydration, so it has nothing to do with the league's drug policy.) The test strips cost only a few cents.

"That is outstanding practice," said Doug Casa, COO of the Korey Stringer Institute, a non-profit named after the Minnesota Vikings offensive lineman who died 13 years ago. "Urine checks before are the best way to know if someone is hydrated prior to the start of exercise, short of a blood draw.

"This is pretty common at the college and pro level. Even some high schools will spot check this in athletes who have chronic hydration issues."

The NFL has made major strides when it comes to preventing heat illness since Stringer died during training camp. The league has also worked to limit such deaths in youths sports, including partnering with the Korey Stringer Institute. KSI is based at the University of Connecticut, where Casa is a professor of kinesiology and director of athletic training education.

Heat stroke deaths remain an issue nationwide as the National Athletic Trainers' Association reports that there have been 20-22 deaths in all levels of athletics since the start of 2010. It remains one of the three leading causes of deaths in sports and is No. 1 during the summer months, according to NATA.